Cognitive behavioral therapy is an efficacious treatment of social anxiety disorder, however less is known about how therapy leads to change. To better understand how treatment leads to meaningful changes for clients, which will ultimately lead to improvements in existing treatments, it is essential that research examines multiple aspects of change with a focus on how these various change agents interact to produce clinically significant change. Therefore, the overall goal of this research projects is to test aspects of a multidimensional model of change within cognitive behavioral therapy for social anxiety disorder. Specifically, this research aims to examine the role and interaction of two proposed mechanisms of change (decentering and emotional processing) longitudinally across the course of Cognitive Behavioral Group Therapy (CBGT) for social anxiety disorder. The study aims to examine the extent to which decentering, or the ability to observe thoughts and feelings as objective events in the mind, increases over the course of CBGT and whether this increase In decentering is related in decreases in symptoms of anxiety and increases in quality of life. Futher, this study will examine the interaction between decentering and emotional processing and whether it is a combination of these mechanisms that leads to the lowest levels of anxiety and highest levels of quality of life at the end of therapy. The results of this study will serve as a preliminary test of a multidimensional model of change that proposes that it is a combination of these factors that leads to therapeutic change. This preliminary test of the multidimensional model of change will help determine the direction df future investigations into therapeutic change mechanisms and intervention development for the treatment of anxiety disorders.